Understanding WiMAX (Chapter 10)
ENE 490
MON 13:30-16:30
Asst. Prof. Dr. Suwat Pattaramalai
Understanding WiMAX
WiMAX Network Architecture
End-to-end network system architecture, three stages development
Stage 1: the use case scenarios and service requirements are listed
Stage 2: the architecture that meet the service requirements is
developed
Stage 3: the details of the protocols associated with the architecture
are specified
This chapter will focuses mostly on the stage 2
WiMAX network reference model, end-to-end protocol layering,
network selection and discovery, IP address allocation, functional
architecture and processes associated with security, QoS, and
mobility management
Understanding WiMAX
General Design Principles of the Architecture
Functional decomposition: Features are decomposed into functional
entities without specific implementation assumptions about physical
network entities
Deployment modularity and flexibility: enough to not preclude a
broad range of implementation and deployment options
Support for variety of usage models: support the coexistence of
fixed, nomadic, portable, and mobile usage model
Decoupling of access and connectivity services: unbundling of access
infrastructure from IP connectivity sevices
Support for a variety of business models: logical separation between
(1) network access provider, NAP; own and/or operates the access
network, (2) network service provider, NSP; owns the subscriber and
provides broadband service, (3) application service providers, ASP;
Extensive use of IETF protocols: Internet Engineering Task Force
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General Design Principles of the Architecture
Support for access to incumbent operator services: through
interworking functions
Network Reference Model
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Network Reference Model (NRM)
(1) mobile stations used by the subscriber to access network
(2) access service network (ASN) owned by NAP
(3) connectivity service network (CSN) owned by NSP
ASN Functions, Decompositions, and Profiles
Understanding WiMAX
ASN gateway: location management and paging; acts as a
server for network session and mobility management;
performs admission control and temporary caching of
subscriber profiles and encryption keys; acts as an
authenticator and AAA; client/proxy, provides mobility tunnel
establishment and management with BS; performs service
flow authorization (SFA); provides foreign-agent
functionality; performs routing (IPv4 and IPv6) to selected
CSNs
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CSN Functions:
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Reference Points: a conceptual link that connects two groups
of functions that reside in different functional entities of the
ASN, CSN, or MS
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Protocol Layering Across a WiMAX Network
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Protocol Layering Across a WiMAX Network
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Protocol Layering Across a WiMAX Network
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Network Discovery and Selection: 4 procedures
NAP discovery: MS discover all available NAPs within a coverage area
NSP discovery: MS discover all NSPs that provide service over given ASN
NSP enumeration and selection: MS make a selection from the list of
available NSPs by using an appropriate algorithm (auto or manual)
ASN attachment: MS indicates NSP selection by attaching to an ASN
associated with the selected NSP and by providing its identity and home
NSP domain in the form of a network access identifier
IP Address Assignment
Dynamic Host Control Protocol (DHCP): primary mechanism to allocate a
dynamic point-of-attachment (PoA) IP address to the MS
To support IPv6, the ASN includes and IPv6 access router (AP), for mobile
IPv6, MS obtains the care-of-address (CoA) from the ASN, and a home
address (HoA) from the home CSN
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Authentication and Security Architecture
AAA framework should meet following:
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AAA Architecture Framework: pull model 4 steps
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Authentication Protocols and Procedure
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Authentication Protocols and Procedure
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ASN Security Architecture
(1) authenticator defined in EAP specifications
(2) authentication relay is the functional entity in a BS
(3) key distributor holds the keys generated during EAP exchange
(4) key receiver hold the authentication key
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Quality-of-Service Architecture
Dynamic service flow follows three generic steps
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Quality-of-Service Architecture
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Mobility management
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Mobility
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Mobility
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Mobility
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Radio Resource Management
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Paging and Idle-Mode Operation
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Summary and Conclusions